1. Field of the Invention
The present invention concerns methods and devices to generate transmission signals via multiple transmission units of a transmission system for a magnetic resonance tomography system.
2. Description of the Prior Art
Magnetic resonance (MR) apparatuses, in particular for the examination of patients by magnetic resonance tomography, are known from DE10314215B4, for example.
Modern magnetic resonance (also called MR or MRT) systems operate with coils to transmit radio-frequency pulses for nuclear magnetic resonance excitation and/or to receive induced magnetic resonance signals. A magnetic resonance system typically has a permanent magnet or a superconducting coil that generates an optimally homogeneous magnetic field—known as a basic magnetic field (B0)—in an examination region. A whole-body coil (also called a body coil or BC) is permanently installed in the MR apparatus, and multiple small local coils (also called surface coils or LCs are available for placement on or around the patient). Image data from selected regions of the subject or patient to be examined are obtained with gradient coils for three spatial axes, from which images of a patient can be generated. Spatial coding in magnetic resonance tomography is typically achieved with a gradient coil system with three independently controllable, magnetically orthogonal gradient field coils. The orientation of the coding plane (“gradient field”) can be freely selected by superimposing the three freely scalable fields (in three directions X, Y, Z).
In order to radiate the desired shapes (for example the time curves of RF transmission signals) in a transmission array for MR systems—thus to transmit or to induce the transmission—the individual transmission units must be supplied with the corresponding transmission data that define the shapes. These data are transferred to the transmission units via respective data paths from one or more control units.
For example, it is known to use a parallel structure that provides a separate data path on which the data can be transferred in real time (U.S. Pat. No. 6,969,992) for each unit.